Natural fibers like cotton and wool must be more sustainable than polyester, right? Turns out it's not so simple. It takes 1400 to 3400 gallons of water to produce just one pound of cotton, enough for about 2 T-shirts! Only one third of the cotton plant is useful for clothing, the rest end up as animal feed, food fillers, and cotton-seed oil, a base for margarine. This sounds like a good use of waste material until we consider the heavy use of pesticides and herbicides due to loose regulations since cotton is not a "food" crop. Cotton covers 2.5% of he world's cultivated land, yet uses 16% of the world's insecticides. For example, Aldicarb, cotton's second best selling insecticide can kill a man with just one drop absorbed through the skin, yet it is still used in 25 countries including the US, where 16 states have reported it in their groundwater.
Since the 2000's, genetically modified cotton has promised lower pesticide use by engineering the cotton plant itself to produce the Bt toxin which kills insects. Although this may reduce pesticide use, these varieties are often also designed to be resistant to herbicide. This way, herbicide can be sprayed on the entire field and only the GMO-cotton plants would survive. This results in a much higher dose of herbicide in the plants. Now up to 88 percent of cotton is genetically modified. It's still highly debatable whether GMO-cotton helps or worsens environmental impact.
Equally concerning is the use of synthetic nitrogen fertilizers which leads to nitrous oxide (N2O) emissions, which are 300 times more potent than CO2 as greenhouse gas. On top of all of the above, the conversion of cotton into clothing requires many hazardous materials including silicone waxes, harsh petroleum scours, softeners, heavy metals, flame and soil retardants, ammonia, and formaldehyde, just to name a few.
Comparatively, production of polyester from petroleum uses almost no water, no farm land, and generates very little waste. It does take more electricity to make polyester though, about 18kWh rather than between 8-9 kWh for cotton per pound of fiber. For recycled polyester, it takes only about 13 kWh per pound of fiber. Unlike cotton which degrades during the recycling process, recycled polyester remains the same quality as when it started.
Next time you're offered a free T-shirt, think about the environmental impact! Although organic cotton uses precious water and land resources even though its pesticide footprint is small. In the next post, I'll discuss the real cost of cotton alternatives like polyester, nylon, hemp, bamboo, and wool. In the mean time, don't buy clothes that you don't need, and consider used and vintage clothing to reduce the need for new cotton. Also, tell us what's your take on wearable sustainability? What's your favorite fabric? Would you give up buying new cotton in light of these devastating facts?
Sources and Additional Reading:
(1) Gail Baugh, lecturer of Apparel Design & Merchandising,San Francisco State University
(2) Organic Trade Association, Cotton and the Environment
(3) GMO Compass, Cotton
Jennifer Zhao is a local mom and owner/founder of Organiworks, a retailer of high quality natural and organic skin care products serving the Capital Region and beyond. Jennifer is passionate about sustainable living and also writes a blog on choosing green personal care products. Please leave your comments or questions below or connect via Facebook or Twitter.